Pulling elbow



W. J. SCOTT PULLING ELBOW Oct. 11, 1960 2 Sheets-Sheet 1 Filed Oct. 15. 1957 I jziarneys W. J. SCOTT PULLING ELBOW Oct. 11, 1960 2 Sheets-Sheet 2 Filed Oct. 15. 1957 United States Patent PULLING ELBOW William J. Scott, Sycamore, Ill., assignor to Ideal Industries, Inc., Sycamore, 111., a corporation of Delaware Filed Oct. 15, 1957, Ser. No. 690,386

3 Claims. (Cl. 285-127) This invention is in the field of conduit fittings and is in the nature of what is referred to in the trade as a pulling elbow. The purpose of a pulling elbow is to connect two conduit pipes together at right angles and to turn the wires contained in the pipe around the. thus formed corner. It is the usual practice to pull the wires through one conduit and then to stuff them through the other. The pulling elbow normally has two hubs disposed at right angles and formed integrally on what may be considered a unitary hollow body; A cover surface with an enlarged opening leading into the hollow body or housing is disposed at 45 to the axes of the two hubs and a suitable cover is removably attached to the cover surface. When the wires are being pulled through one conduit and stuffed into the other, the cover is removed 'and after-the operation is complete the cover is replaced and secured. Connections are not made in the elbow.

A primary object of my invention is a new and improved pulling elbow constructed to protect'the insulation on the wires to a maximum extent.

Another object is a pulling elbow of the abovetype which is simple and inexpensive to make.

Another object is a pulling elbow constructed toprovide an unobstructed sighting through either hub.

Another object is a pulling elbow which will not choke at the throat.

Another object is a pulling elbow of the above type which may have two female hubs or one female and one male hub.

Another object is a pulling elbow with a cover mounting arrangement that protects both the threads of the hubs and also the insulation of the Wires.

Another object is a pulling elbow of the above type with a well rounded convex throat to protect the wire insulation.

Other objects will appear from time to time in the ensuing specification and drawings in which:

Figure 1 is a side view of my elbow;

Figure 2 is an axial section of my elbow;

Figure 3 is a View in the direction of the arrows 3-3;

Figure 4 is a section along line 4--4 of Figure 2;

Figure 5 is a section, similar to Figure 2, of a mod-ified form; and

Figure 6 is an end wiew of Figure 5.

In Figures 1 and 2 the body or housing of the pulling elbow has been indicated generally at 10 and includes two hubs 12 and 14 disposed at right angles and extending away from a cover surface 16. The exterior of each hub may be somewhat cylindrical and since, in the form shown iu Figure 3, the housing and hubs are symmetric on each side of a center plane 18, I may apply the same reference numerals to each hub and its adjacent parts.

Considering the hub. 12, it has a central bore 20 which is generally open and extends through into the interior of the housing or body. A portion or area of the bore is threaded, as at 22, and terminates in an annular groove 24. The entrance to the bore may be tapered, as at 26, if desired, defining an included angle of approximately or the like.

The axis 28 of the hub 12 intersects the cover surface 16 at the point 30. It should be noted that the axis 32 of the other hub 14 also intersects the cover surface at the point 30. This is to say that the two axes 28 and 32 of the two hubs intersect at a point that lies in the general plane of the cover surface, which is important for reasons to be set forth hereinafter. I

The annular groove 24 at the end of the threaded section or area 22 has an abrupt upstanding annular wall or shoulder 34 which functions as a pipe stop. This is to say that when a threaded conduit pipe is fully screwed into the section 22, the forward edge will abut the shoulder 34. Between the bores of the two hubs, I provide a well rounded internal convex. shoulder 36, which on each side flows smoothly into the pipe stop or shoulder 34. The diameter 38 of the bore between the pipe stop or shoulder 34 and the convex corner 36 is an important feature. This diameter is related to the dimensioning of the threads 22 such that the internal diameter of the conduit pipe will always be greater than the diameter 34. Accordingly, when insulated wire passes around the Well rounded corner 36 from one conduit pipe to another, it will not contact the edge of the pipe, which is often rough and burred, but will rest on the well rounded shoulder and will flow tangentially ofi of the face, each hub will not be interrupted by any projecting portions of the housing or body that rise'above the general plane of the cover surface 16. This is to say that if the pulling elbow is viewed along either theaxis 28 or the axis 32 straight through the bore of the hub, the sight will not be obstructed. In'other words, the extension of either bore would not strike a portion of the housing since it is totally aligned with the opening 40 in the cover surface. l

As shown in, Figure, ,3, the opening 40 in the cover surface is elongated in the direction of the plane through the hub axes 28 and: 32. I provide a suitable cover 41 and gasket 43. of rubber or otherwise which closes the opening 40 and conforms to the. cover surface. While the cover'surface is well rounded at each end, as at 42 and 44, the sides of the opening 40 do not follow but are rather square cut,as at 46, and 48, thereby providing areas or surfaces 50 and 52 for mounting the 7 cover plate. In each such area, I provide screw holes 54 and 56 which lie on or in the general plane of the hub axes 28 and 32 and, as shown in Figure 3, open into the annular groove or channel 24.

This has the distinct advantage that when the screw hole is bored and tapped, the burrs around the surface where the hole opens into the bore will not interfere with the threads 22. Nor will these burrs in any way contact the insulation of the wires since it will be noted in Figure 2 that the opening of the screw hole is set back from the bore of the hub. v

To prevent choking of the elbow at the throat, I provide a well rounded cross section throat 58, in Figure 4, which is swung on a circle about the point 60. It should be noted that the center point 60 lies on the line or plane 18 perpendicular to the cover surface at the intersecting point 30 of the two hub axes, but is spaced below the cover surface -16 or between the curved throat surface 58 and the cover surface. It is important that the pivot point or center 60 of the curved throat surface 58 be spaced well below the cover surface, as shown in Figure 4.

' opens into this cavity.

' "The? invention m a T "2,955,851

which one hub 62 maybe internally tlileadie'cl Or female while the other 64 may be externally threaded. In this case, it. will be noted that the well roundedjnternal convex corner 66- flows sni'oothlyflinto' the interior of the" bore 68'for the male hub and.an. ar'inular. groove, as at" 10, for, the female hub is not necessary. 111 this case,

7 .I' provide a cavity or ofiset 72 which lies outside. of the cylindrical bore 68. The screw'hole 74 for flie cover the screw hole :will not in any way interfere with the rno'vementlof wire through the smooth bore ofthe hub, but will; be' ofi'set in a cavity of its own. 'The" details of this female hub 62' as to the'annulargroove OY'ChfllP nel 70, the dimensioning, and the; screw hole may. be much the same asin the previous form; 7 i V In both cases, as shown for example in the Figure 3{ Thus, the bun-fed opening of.

I claims.

wire'back and forth, its only point of contact will be the well rounded convex corner which, dueto the backto-back arcs 58 and 66 in Figures 4' and 5, provides a saddle effect. Additionally, the arc of the throat is swung about a circle which lies well below the cover surface, thereby preventing choking at the throat. 7

While I have shown and described the preferred form and suggested several modifications it will be apparent that many additional changes, modifications, substitutions and alterations maybe made without departing from the i'nyentions fundamental theme; I, therefore, wish that my invention be unrestricted except as by the appended Iclaim: ii 1. In a pulling'elbow, a hollowhousing having a pair of open' bored conduit receiving integral hubs disposed with their axes generally at right angles to each other,

speciesal find it convenient toroundfthe edges 46' and"48 e opening 40 through the cover surface, as indicated at76and78fin Figure a t j The use; operation and function of; my invention-are asfollows:

posed perpendicular to each otherwith their axes intersecting in' the plane of the cover surface which} is dis I p'osed at45" to thetwo axes. Both hubsmay be female with internal threads, but one mightbemalewith external" threads; j

* Allot the feinalehubs the internalthreads are provided: with an annular channel or groove-just back is a pulling elbow with two hubs i of or: behind thethreads so that anabrupt should'e'r is provided 'as a pipestop, A well rounded convex corner interconnectsthe'bore ofithe two hubs' and" tliediameter ofthe'bore'ofthehub at the corner is alwaysless than the" internalfdiameter of the conduit pipje. 'Thus-,-the-' insulationofthe wires will now tangentially 0E of'the' convex'corner and will' not touch the sharp burred edgeof the-pipe, but -will pass overit} and flow smoothly down the-pipes, 1 I 7 a p The screw hole for the-cover" opened: the case of a exit does not in any way interfere with the threads; or

aicover surface on the housing generally at 45 to the hub axes; an aperture in the cover'surface providing accessinto the housing, at least one of the hubs having an internally threaded area, an annular groove bet ween: the threaded area and aradially inwardly extendingconvex corner, an annular shoulderforrned bysaid radially inwardly extending convex corner" and saidgroove and functioning as a conduit stop, the aperture in the cover surface being' elongated in the generalplane of the hub axes; and screw holes spacedfrom each end of the aperture' and disposed in the plane of. the hub axes, each screw 'holeadjacent a hub with an internally threaded area openinginto-the annular groove in the hub bore.

. 21 The structure of' claim '1 further characterized in that'both' hubs have internally threaded areas. with an annula'r'groove betweenthethreadedareas and the. con: vex= corner with-screw holes openinginto-the groove of each hub; 7 V

. 3. The. structure that, the axial projection of the boreitormed' by the radially inwardly extending convex corneniutersecits the 40 ,fe'malehub, into theannular channel so that the burred: V

withgthe insulation or movementof the wiresp If one.

of the hubs is a male hub, a separat'e cavityis provided so that the burr'edmpening isofiset and out oftheway.

If a. sightistakendown the axis of either: hub, there? 'willbe" no projections or obstructions in the.-.way.-

has the distinct advantage that when is; being: pulled;

' throughon'e'ofthe pipesg it willnot be bent over'or in; contact necessarily with a part, of the housing; The

same is true when the wire is being-stufied through the otherhub.- During any subsequent; movement of the general plane of the cover surfacewithimtheperipheral outline otthe cover surface: aperture so that wires being pulled through the elbow will not have their insulation: marred. f

References Cited in thefile' of'fliig t nfl I UNLTED STATES PATENTS,

916,931a .McMurtn'e Mai..30,- 1909 960,744 Vogel' June 7,, 1910 1 ,463,461 Davis July 31, 1923 1 ,650,233- .Plunkett Nov.: 22,1927 1,819,985 Boytonlm'. -Q. Aug, 18, 1931 2,067,644

ofj claint 1 further-' characterized. 

